Computerized systems have made a significant contribution towards the advancement of modern society and are utilized in a number of applications to achieve advantageous results. The transmission of data using electronic means is one such example that has benefited from the utilization of computerized systems. As the number of consumer electronics incorporating wireless networking functionality have increased recently, the need for improved wireless connectivity has also increased in response. Wi-Fi is the trade name for the popular wireless technology used in home networks, mobile phones, video games and other electronic devices that provide a form of wireless networking capability. In particular, the term Wi-Fi is interpreted to include the various IEEE 802.11 technologies (which include 802.11n, 802.11b, 802.11g and 802.11a).
A Wi-Fi enabled device such as a personal computer (PC), video game console, mobile phone, portal audio player or personal data assistant (PDA) can connect to the Internet when within range of a wireless network connected to the Internet. The coverage of one or more interconnected access points—also called a hotspot—can comprise (and provide wireless connectivity to) an area as small as a single room or as large as many square miles covered by overlapping access points.
A wireless access point (WAP) connects a group of wireless devices (also called “clients”) to an adjacent wired local area network (LAN). An access point is similar to a network hub, relaying data between connected wireless devices in addition to a (typically) single connected wired device, most often an Ethernet hub or switch, allowing wireless devices to communicate with other wired devices in the network.
However, for a wireless device to maintain constant Wi-Fi connectivity, power must be consumed at a greatly advanced rate. A conventional solution to this issue has been to incorporate a mode of operation referred to as power saving mode (PSM) in many wireless network devices. A client in a power-saving mode operates in a “sleep” state, during which data is neither received nor transmitted by the client, and power consumption is extremely low. Conventional applications include automatically changing the operating mode of a device to the power-saving mode if a period of idleness for the client exceeds a certain duration.
In conventional PSM schemes, a client commencing operation under PSM will send an indication to the access point. The client subsequently goes into a sleep state, and data received in the access point intended for the sleeping client is buffered in the access point until the client is awake (no longer in PSM). Meanwhile, the client wakes up periodically (e.g., every 100 ms) to receive a beacon from the access point to determine if the access point has any outstanding data for the client. If outstanding data is detected, the access point will send the client a communication, typically in the form of a traffic indication map (“TIM”) beacon indicating so. The client subsequently responds to a TIM beacon by sending a poll message to the access point and discontinues operating in a PSM and remains active until the outstanding data is received. Once the outstanding data is received, the client may resume operation under a PSM. Likewise, the client may (re)commence operating in an active operating mode to send packets.
Unfortunately, the efficacy of this solution is often compromised within proximity to other wireless network devices. For example, when a client in a PSM sends a poll message to the access point in response to a TIM beacon indicating the presence of outstanding data intended for the PSM client, and the PSM client will typically, remain active to receive the packets. However, the access point may also be transmitting data to other wireless network devices. A typical access point distributes data received according to a data structure such as a queue. Thus, if the data intended for the PSM client is detected but not at (or near) the front of the transmission queue, the PSM client will remain in an active mode whilst the data ahead of the data intended for the PSM client is delivered to its intended recipients (other clients).
Furthermore, the application of power saving modes is not effective for all Wi-Fi applications. Voice over Internet Protocol (VoIP) is a popular telecommunications application which allows users to communicate verbally over an established Internet connection. However, operating in a PSM often adds latency to the transmission of data packets (through the periodic sleeping). The nature of verbal communication typically involves a rapid exchange of data packets, rendering unnecessary latency highly undesirable. Accordingly, devices engaging in VoIP may be unable to take advantage of the benefits of a PSM. Likewise, PSM clients operating in proximity to (e.g., using the same access point as) a client using a VoIP application may suffer from a decreased effectiveness in the PSM due to the rapid transfer of data packets by the client executing a VoIP application. In addition, other Wi-Fi applications, such as active web-browsing and gaming over the Internet or LAN, may be subject to the same concerns.
Recent standards extend power-saving support for VoIP. For example, WMM® Power Save is a recent addition to WiFi standards and allows an access point to send data to a client immediately, using high priority, in response to a client that sends any data frames to the access point. While this mechanism can help VoIP clients that periodically send data to return to a low-power state quickly, it provides no such benefit to VoIP clients that are not periodic (e.g., due to silence suppression) or other clients that perform web browsing or other non-periodic network activities.